The present invention relates generally to product dispenser systems and, more particularly, to a method and device for automatically delivering a concentrated product solution as necessary to maintain a predetermined concentration of the solution at a point of application.
Large amounts of liquid and powdered detergent are used by commercial organizations such as carwashes, laundries, and restaurants. The liquid detergent is normally purchased in large cylindrical shipping containers that typically have a 5, 6, 15, 30, or 55 gallon capacity. Likewise, powdered detergent may be purchased in the same capacities but also in smaller capacities generally weighing between 5 and 15 pounds.
In a commercial establishment such as a restaurant, the detergent is generally used in automatic dishwashers. Each dishwasher has a wash tank that carries a large volume of detergent solution. The dishwasher uses this detergent solution over and over again for a period of time, such as four hours, until it is replaced by a new solution. During normal usage, however, some of the detergent solution is drained off along with food particles and grease removed by the dishwasher to keep the remaining solution as clean as possible. Water is added to the wash tank to maintain a proper level which, of course, reduces the concentration of the solution in the wash tank.
In order to keep the detergent solution in the wash tank at the proper concentration, detergent must be added periodically. The most simple prior art approach to increasing the concentration of detergent was to have an employee periodically add powdered detergent to the dishwasher wash tank. This was not a satisfactory approach. For one thing, it required more or less constant attention by an employee. Further, it was almost impossible for the employee to tell when to add detergent and how much to add. The result was that the detergent concentration in the wash tank fluctuated widely over a period of time.
One prior art approach to improving this situation provides a system that automatically adds concentrated detergent solution to the wash tank when its concentration drops below a specified level. To accomplish this, suitable electrodes are placed in the wash tank to measure solution conductivity. Also a source of concentrated detergent solution is provided. When the conductivity drops below a certain level, a driver device is energized to introduce clean concentrated detergent solution into the wash tank.
Another prior art approach provides a reservoir having an open top covered with a hinged lid. A shipping container, preferably about 10 pounds, having a sufficiently small mesh screen is inverted over the receptacle with the screen and an opening in the reservoir being aligned. A single, upwardly directed water spray nozzle is mounted within the reservoir such that, when the nozzle is energized, the resulting spray wets the entire bottom surface of the screen positioned above the nozzle. A saturated detergent solution results, which falls through the screen into a point of application. An electrical probe is used to turn on the water to the nozzle until the proper solution level is reached in the dishwasher wash tank.
The screen used with these prior art systems is generally a flat or a modified flat conical screen and is used in combination with a single pulsing spray nozzle. These systems are only marginally acceptable for commercial usage because they often result in "channeling" of the detergent in the container, i.e., vertical channels are formed in the powdered detergent above the screen. A desirable system would not form channels but would cause even hydration of the product about one-half inch above the screen. When channeling occurs, a large surface area of the powdered detergent is exposed to the spray and thus becomes hydrated. During periods of non-use, this hydrated detergent dries and can become caked. The caked product is not readily soluble. If the product in the container becomes channeled and caked, it is then difficult to dissolve sufficient detergent to provide the necessary solution concentration in the dishmachine wash tank. Too much powdered detergent is also left in the container and wasted.
Although liquid detergents continue to be utilized in the dishmachine, they are mostly confined to "batch" type dishmachines where the wash tank solution is emptied after each wash cycle. Product is normally purchased in one or five gallon open-ended containers.
Another prior art system is disclosed in U.S. Pat. No. 5,086,980, which is hereby incorporated by reference and which discloses a container capped with a slitted septum cap, and an open-ended, wall-mounted dispensing device in which the top, slitted cap end of the container is received. A penetrating device extends through the slit in the septum, and the sides of the slit close around the penetrating device to prevent material from escaping unless the sides are forced apart. A peristaltic pump is used to displace concentrated products into a pressurized line on a dishmachine. Although spillage and leakage is reduced compared to other prior art systems, this prior art system fails to eliminate spillage and leakage. As a result, high costs are incurred due to leaking containers in storage and shipment. Further, safety can be compromised due to container spillage from faulty septum slits.
An object of the present invention is to provide a dispensing system with substantially no potential for leakage during storage, shipment, and use. It is a further object of the present invention to provide a dispensing system that eliminates the possibility of the use of the wrong container or material in the dispensing system.
The present invention utilizes a self-sealing shipping container of, preferably, homogenous, viscous material. A tamper-evident enclosure cap is preferably attached to the container at the time of production. A wall-mountable receptacle for the product container is provided, having an upwardly facing opening corresponding generally in size to the top of the shipping container. The device is designed to accept product containers for specific applications, draw product out of the containers, verify product availability, and deliver available undiluted product to the end use point when needed, preferably with a peristaltic pump.
The shipping container is positioned over the receptacle, with the enclosure cap in line with an opening of the receptacle. The shipping container has a key or a keyway, and is lowered into the receptacle so that the key is received in a keyway of the receptacle or a key of the receptacle is received in the keyway of the container. The container has a septum that is pierced by a container piercing device, such as a single, cuneiform hollow piercing device which is mounted in the bottom of the receptacle to remove the product from the shipping container when the pump is activated.
The device according to the present invention has proven to be much superior in operation to the prior art systems. The ability of the peristaltic pump to maintain a consistent concentration level in the wash tank has far surpassed other water driven systems of the prior art. The shipping container is entirely enclosed and thereby eliminates the hazards of concentrated products coming into contact with users. Moreover, water consumption at the point of use is reduced, particularly in comparison to devices where caking of product tends to occur.
The ability of the device of the present invention to consistently deliver a homogenous product solution has enabled further development of a "probeless" dispensing system in conjunction with the conventional electrode solution concentration measuring system. Based on timed product feed proportional to water usage rates, the present invention permits maintaining a consistent concentration level in the wash tank in various standard models of dishmachines, including single rack and conveyor-type machines.
In accordance with one aspect of the present invention, a device for dispensing a product solution is provided. The device includes a container for a product solution, the container having a top end, the top end including a top end, the top end including a first opening, a continuous septum extending over the first opening, and a second opening, a microporous, hydrophobic membrane extending across the second opening. The device also includes a receptacle for receiving the container in an inverted condition, the receptacle including a seat portion for receiving the top end of the container, the seat portion including an upwardly extending, hollow piercing device capable of piercing the septum. The device also includes a pump for withdrawing product from the container through the piercing device.
In accordance with another aspect of the present invention, a device for dispensing a product solution is provided. The device includes a container for a product solution, the container having a top end, the top end including a first mating device and an opening, the container including a microporous, hydrophobic membrane extending across the opening. The device also includes a receptacle for receiving the container in an inverted condition, the receptacle including a seat portion for receiving the top end of the container, the seat portion including a second mating device for mating with the first mating device and a device for extending into the container. The device also includes a pump for withdrawing product from the container through the device for extending into the container.
In accordance with yet another aspect of the present invention, a method for dispensing a product solution is provided. According to the method, a container of product solution is inverted such that a top end of the container faces downwardly, the top end of the container including a top end, the top end including a first opening, a continuous septum extending over the first opening, and a second opening, a microporous, hydrophobic membrane extending across the second opening. The container is positioned in a receptacle such that the top end of the container is disposed in a seat of the receptacle, the seat of the receptacle having a hollow, upwardly extending piercing device. The septum is pierced with the piercing device such that part of the piercing device is disposed inside of the container. The product is withdrawn from the container through the piercing device.